Activity of Cytochrome P450 Monooxygenase (CYPs) Metabolic Enzymes as Markers of Insecticide Resistance in Anopheles vagus Muara Enim Mosquitoes, Indonesia

A B S T R A C TThe use of synthetic pyrethroids in insecticide-treated bed nets (LLINs) and sprayform (IRS) has been carried out since 2012 in Muara Emil Village and since 2016 inall villages in Tanjung Agung District, Muara Enim Regency. Biochemical resistancecan occur to the enzymes that play a role in detoxifying the insecticide. This studyaims to identify whether there is an increase in the levels of the enzyme CytochromeP450 monooxygenase (CYPs) through the enzyme biochemical test on the malariavector mosquito Anopheles vagus originating from Pagar Dewa Village and MuaraEmil Village, Muara Enim Regency. The sample of female Anopheles mosquitoes wasnot full. Blood was taken at night using the resting collection method. Mosquitoesthat have been identified as Anopheles vagus species are used to check CYPs enzymelevels using the ELISA method. The results of the biochemical test showed thatenzyme levels increased from the Muara emil and Pagar Dewa village mosquitoeswith a percentage of 71% and 61.53% (with cut off point OD> 0.165). The value ofCYPs enzyme levels for mosquitoes from Muara Emil village was higher than that ofthe mosquitoes from Pagar Dewa Village (mean 0.005027 ± 0.007). The increasedactivity of the CYPs enzyme plays a role in the detoxification of synthetic pyrethroidinsecticides that can cause resistance. The high levels of enzymes from the villagesof Muara Emil and Desa Farah Dewa are in line with intensive insecticide exposurein eradicating malaria vectors in the highest malaria transmission areas in MuaraEnim Regency.

Download Full-text

The Impact of Insecticide-treated Bed Nets on Parity and Malaria Sporozoite Infectivity of Anopheles Species in Kamuli District, Uganda

International Journal of TROPICAL DISEASE & Health ◽

10.9734/ijtdh/2020/v41i130243 ◽

2020 ◽

pp. 35-43

Author(s):

Fredrick G. Kabbale ◽

Anne M. Akol ◽

Kaddu J. Baptist ◽

Ambrose W. Onapa

Keyword(s):

Behavioural Change ◽

Malaria Vectors ◽

Bed Nets ◽

Anopheles Mosquitoes ◽

Before And After ◽

Additional Protection ◽

Falciparum Sporozoite ◽

Insecticide Treated Bed Nets ◽

The Impact ◽

Intervention Zone

Background: The main objective of treating bed nets with insecticides is to affect the mean longevity of the main vector population, and consequently the vector density and sporozoite rates. Objective: This study aimed at establishing the impact of insecticide-treated bed nets (ITNs) on the longevity and ability to transmit malaria sporozoites by the vector species as an assessment of effectiveness of the ITN intervention in Kamuli district, Uganda. Methods: Indoor human-biting mosquitoes were trapped in three randomly selected houses in two separate nights using battery-operated CDC light traps in both intervention (with ITNs) and non-intervention villages (without ITNs). The female anophelines were dissected and their parity rates and Plasmodium falciparum sporozoite positivity compared between the two zones. A sporozoite Enzyme-Linked Immuno Sorbent Assay, ELISA, was used to detect the presence of P. falciparum sporozoites in the parous vectors in both zones. The parity and P. falciparum sporozoite infectivity were compared between the two zones using the Kruskal-Wallis rank sum test of the R-Statistics software. Results: Out of the 166 Anopheles mosquitoes dissected, 37.3% (19 out of 51) and 53.9% (62 out of 115) were parous in the intervention and non-intervention zones, respectively, indicating that parity of the mosquitoes was higher in the non-intervention (p = 0.005). Infectivity of the vectors in the non-intervention exceeded that in the intervention zone (p = 0.032), with active sporozoite transmission observed before and after bed time in the non-intervention zone. Conclusion: Results showed that ITNs had impacted on the survival and consequently the density of the older malaria vectors, and on their ability to transmit Plasmodium sporozoites. This calls for intensification of use of this effective malaria control strategy, coupled with behavioural change communications strategy to promote correct use, as well as use of other interventions like repellents to provide additional protection especially before and after bed time.

Download Full-text

Intensity and mechanisms of deltamethrin and permethrin resistance in Anopheles gambiae s.l. populations in southern Benin

Parasites & Vectors ◽

10.1186/s13071-021-04699-1 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Hermann Watson Sagbohan ◽

Casimir D. Kpanou ◽

Razaki Osse ◽

Fortuné Dagnon ◽

Germain G. Padonou ◽

...

Keyword(s):

Insecticide Resistance ◽

Detoxification Enzymes ◽

Malaria Vectors ◽

Bed Nets ◽

Resistance Allele ◽

Resistance Mutations ◽

The Difference ◽

Study Sites ◽

Insecticide Treated Bed Nets ◽

Southern Benin

Abstract Background Insecticide resistance is threatening the effectiveness of efforts to control malaria vectors in Benin. This study explores the levels and mechanisms of insecticide resistance in An. gambiae s.l. to pyrethroids. Methods Larvae were collected from August 2017 to July 2018 in five communes in southern Benin (Adjohoun, Allada, Bohicon, Cotonou, and Porto-Novo) representing diverse ecological regions, and were reared in Benin’s insectary. Two- to five-day-old female mosquitoes from each district were exposed to multiple doses of deltamethrin and permethrin (1×, 2×, 5×, and 10×) using the WHO insecticide resistance intensity bioassay. The effect of pre-exposure to the synergist, piperonyl butoxide (PBO), was also tested at different pyrethroid doses. Molecular allele frequencies of kdr (1014F) and ace-1R (119S) insecticide resistance mutations and levels of detoxification enzymes were determined for mosquitoes sampled from each study area. Results An. gambiae s.l. were resistant to pyrethroid-only exposure up to 10× the diagnostic doses in all the study sites for both deltamethrin and permethrin. Mortality was significantly higher in An. gambiae s.l. pre-exposed to PBO followed by exposure to deltamethrin or permethrin compared to mosquitoes exposed to deltamethrin or permethrin only (p < 0.001). The difference in mortality between deltamethrin only and PBO plus deltamethrin was the smallest in Cotonou (16–64%) and the greatest in Bohicon (12–93%). The mortality difference between permethrin only and PBO plus permethrin was the smallest in Cotonou (44–75%) and the greatest in Bohicon (22–72%). In all the study sites, the kdr resistance allele (1014F) frequency was high (75–100%), while the ace-1 resistance allele (G119S) frequency was low (0–3%). Analysis of the metabolic enzymatic activity of An. gambiae s.l. showed overexpression of nonspecific esterases and glutathione S-transferases (GST) in all study sites. In contrast to the PBO results, oxidase expression was low and was similar to the susceptible An. gambiae s.s. Kisumu strain in all sites. Conclusion There is high-intensity resistance to pyrethroids in southern Benin. However, pre-exposure to PBO significantly increased susceptibility to the pyrethroids in the different An. gambiae s.l. populations sampled. The use of PBO insecticide-treated bed nets may help maintain the gains in An. gambiae (s.l.) control in southern Benin. Graphical Abstract

Download Full-text

Host-feeding Preference of Anopheles Species under Prolonged Use of Insecticide-treated Bed Nets in Kamuli District, Uganda: Implications for Vector Control

International Journal of TROPICAL DISEASE & Health ◽

10.9734/ijtdh/2020/v41i130241 ◽

2020 ◽

pp. 16-25

Author(s):

Fredrick G. Kabbale ◽

Anne M. Akol ◽

John B. Kaddu ◽

Enock Matovu ◽

Anne Kazibwe ◽

...

Keyword(s):

Vector Control ◽

Blood Meal ◽

Malaria Vectors ◽

Bed Nets ◽

Enzyme Linked Immunosorbent Assay ◽

Host Feeding ◽

Bed Net ◽

Insecticide Treated Bed Nets ◽

Intervention Zone ◽

Blood Meals

Background: The blood-feeding patterns are crucial in incriminating disease vectors as well as facilitating the design and consolidation of effective vector control interventions in an area. Objective: This study aimed to establish if prolonged use of insecticide-treated bed nets (ITNs) caused a shift in the preferred hosts of the common malaria vectors as the hosts were under the bed net. Such a shift would render ITNs less effective and would probably explain the continued morbidity and mortality due to malaria in the highly endemic Kamuli district. Methods: A total of 3,519 indoor and outdoor human biting female Anopheles gambiae sensu lato and An. funestus mosquitoes were collected from 48 households using human-baited bed net traps. All 187 indoor resting blood-fed anophelines collected were tested by direct enzyme-linked immunosorbent assay (ELISA) for blood meal host identification. Of these, 73 mid guts came from 24 households in villages with a 69% ITNs coverage, while 114 mid guts were from 24 households in non-ITN villages. Results: Blood meal hosts were identified in only 10.96% (n = 8) and 14.91% (n = 17) of the Anopheles blood meals from the intervention and non-intervention zones, respectively. Other blood meals could not be clearly identified. Eight (100%) blood meals in the intervention zone were from humans, while in the non-intervention zone, 15 (88.24%), one (5.88%) and one (5.88%) came from humans, cattle and goat, respectively. These findings demonstrated that the malaria vectors in Kamuli district are anthropophilic, with nearly all the mosquitoes collected from both zones feeding on humans during every blood meal (p = 0.82). This indicated high vector-human contacts, and thus implicating these species as important in the transmission of Plasmodium species and probably other infections. Conclusion: The use of insecticide-treated bed nets is effective for controlling malaria vectors inside houses, evoking universal coverage of houses in the area.

Download Full-text

Preventive Measures Against The Vectors Of Malaria In Akanda, Southwest Gabon: Knowledge, Attitudes, Practices, And Beliefs

European Scientific Journal ESJ ◽

10.19044/esj.2021.v17n21p169 ◽

2021 ◽

Vol 17 (21) ◽

pp. 169

Author(s):

Richard Pamba ◽

Silas Lendzele Sevidzem ◽

Aubin Armel Koumba ◽

Christophe Roland Zinga-Koumba ◽

Audrey Prisca Melodie Ovono ◽

...

Keyword(s):

Preventive Measures ◽

Indoor Residual Spraying ◽

Malaria Vectors ◽

Bed Nets ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Literacy Rate ◽

Beliefs And Practices ◽

Age Cohorts ◽

Insecticide Treated Bed Nets

Background: Reliable data on the Knowledge, Attitudes, Beliefs, and Practices (KABP) of the indigenes of Akanda and its environs on the different approaches to fight against vectors of malaria is lacking. Objective: To evaluate the KABP of the indigenes of Akanda and its environs on the different techniques used to fight against vectors of malaria. Materials and Methods: A cross sectional survey using semi-structured questionnaires was conducted on heads of randomly selected households at Akanda from April to June 2019. Results: We interviewed 369 heads of households and the population had a high literacy rate. It was noticed that 94% of respondents knew that mosquitoes could transmit malaria. More than 80% believed that Insecticide-Treated bed Nets (ITNs) could protect them from malaria infection. There was no preference in ITNs usage with age cohorts and seasons of the year. The ITNs owned by respondents were mostly purchased from shops. Respondents underlined that their reluctance to sleep under ITNs was because of their inability to breath under such conditions. Also, apart from the use of ITNs for malaria control, Indoor Residual Spraying (IRS) using insecticides (mostly Rambo®) purchased from shops and cleaning around house surroundings were practiced by >50% of respondents. Conclusion: Despite respondent’s awareness of mosquitoes as vectors of malaria as well as the use of ITNs, IRS, and cleaning of home surroundings to reduce malaria vectors burden, the ITNs coverage rate is very weak and more sensitization is also required at Akanda in Gabon.

Download Full-text

Pengendalian Vektor Malaria di Daerah Endemis Kabupaten Purworejo, Indonesia

BALABA JURNAL LITBANG PENGENDALIAN PENYAKIT BERSUMBER BINATANG BANJARNEGARA ◽

10.22435/blb.v14i1.290 ◽

2018 ◽

pp. 1-12

Author(s):

Riyani Setiyaningsih ◽

Wiwik Trapsilowati ◽

Mujiyono Mujiyono ◽

Lasmiati Lasmiati

Keyword(s):

Vector Control ◽

Indoor Residual Spraying ◽

Malaria Vectors ◽

Bed Nets ◽

Control Methods ◽

Mosquito Nets ◽

Bioassay Test ◽

Insecticide Treated Bed Nets ◽

And Control ◽

Breeding Place

Purworejo is the endemic area of malaria with the highest case increase occurring in 2015 amounted to 1411 cases. Appropriate control can be performed effectively based on vector bionomics. The aims of study were to determine species, behavior, resistance, and control methods of malaria vectors. Methods were larva andmosquitoes collection, breeding place of mosquitoes surveys, resistance of mosquito and evaluation of the effectiveness of vector control. The research was conducted in Sendangsari Village, Bener District, Purworejo Regency The result of the research showed that An. barbirostris sucked blood indoor, outdoor, and cage. An. balabacensis sucked blood indoor and cage. An. maculatus, An. aconitus, An. kochi, An. Indifinitus, and An. fagus were found to suck blood in the cage. An. maculatus showed resistance to insecticide permetrin 0,75% Indoor Residual spraying (IRS) and the use of insecticide treated bed nets were the vector control perfomed in the area of study. The breeding place of mosquito were in hole around unused fields and pond. Based on bioassay test, the effectiveness of IRS application for one months were not effectively kill An. maculatus while the use of mosquito nets for three months were still effectively kill An. maculatus.

Download Full-text

The influence of feeding behaviour and temperature on the capacity of mosquitoes to transmit malaria

10.1101/604249 ◽

2019 ◽

Cited By ~ 3

Author(s):

Eunho Suh ◽

Marissa K. Grossman ◽

Jessica L. Waite ◽

Nina L. Dennington ◽

Ellie Sherrard-Smith ◽

...

Keyword(s):

Feeding Behaviour ◽

Vector Competence ◽

Thermal Sensitivity ◽

Blood Feeding ◽

Malaria Vectors ◽

Parasite Development ◽

Bed Nets ◽

Behavioural Resistance ◽

Epidemiological Impact ◽

Insecticide Treated Bed Nets

AbstractInsecticide-treated bed nets reduce malaria transmission by limiting contact between mosquito vectors and human hosts when mosquitoes feed during the night. However, malaria vectors can also feed in the early evening and in the morning when people are not protected. Here, we explored how timing of blood feeding interacts with environmental temperature to influence the capacity of Anopheles mosquitoes to transmit the human malaria parasite, Plasmodium falciparum. We found no effect of biting time itself on the proportion of mosquitoes that became infectious (vector competence) at constant temperature. However, when mosquitoes were maintained under more realistic fluctuating temperatures there was a significant increase in competence for mosquitoes feeding in the evening, and a significant reduction in competence for those feeding in the morning, relative to those feeding at midnight. These effects appear to be due to thermal sensitivity of malaria parasites during the initial stages of parasite development within the mosquito, and the fact that mosquitoes feeding in the evening experience cooling temperatures during the night, whereas mosquitoes feeding in the morning quickly experience warming temperatures that are inhibitory to parasite establishment. A transmission dynamics model illustrates that such differences in competence could have important implications for disease endemicity, the extent of transmission that persists in the presence of bed nets, and the epidemiological impact of behavioural resistance. These results indicate the interaction of temperature and feeding behaviour to be a major ecological determinant of the vectorial capacity of malaria mosquitoes.

Download Full-text